NAB Test

Introducing a new Covid Immunity Test

The Covid-19 pandemic has been the catalyst in the new fast-moving trend for patients wishing to understand their immunity. The PremaLabs Neutralising Antibody (NAB) test provide patients a quantitative measurement and not just a binary result. The results will inform patients whether they have sufficient levels of immunity, or if they require a vaccine or booster.


Sensitivity : 99.09% (95%CI: 94.31%-99.95%)
Specificity : 98.89% (95%CI: 93.10%-99.94%)

The Quantitative Test for Covid-19 Neutralising Antibodies

Neutralising Antibodies

The PremaLabs NAB test allows reliable detection and control of neutralising antibodies against the Covid-19 virus. Using the control serum provided by the WHO, the test has been calibrated to give the user a quantitative result in BAU/ml (BAU = binding arbitrary units). This allows a reliable assessment of the immunological status of the test person. The test determines a result that would normally require a 90-minute ELISA blood test on prescription. This test would also have to be carried out in a laboratory, with the blood results being submitted by the doctor. With the PremaLabs NAB test, the patient can have the test done via capillary blood (finger prick) collection and the doctor or pharmacist can view the result within 15 minutes.

Binding Antibody Units

  • The Titre is a measure of the amount of an antibody or antigen (in serology) or of a pathogen (in microbiology) that just causes a biological reaction.
  • Today, the Antibody Titre is often also given directly as a measure of the antibody concentration in a patient’s serum in ng/ml, IU/ml or Binding Antibody Units (BAU).
  • BAU is a WHO normalised and standardised unit that enables worldwide comparability between different testing methods to assess the immunity status after vaccination or the increase in the concentration of antibodies during an acute infectious disease.

Source: Dr. rer. nat. Dipl.-Chem. Andreas Bobrowski. Chairman of the Board of the Professional Association of German Laboratory Physicians.

Frequently Asked Questions

A neutralising antibody (NAB) is an antibody that defends a cell from a pathogen or infectious particle by neutralizing any effect it has biologically. Neutralisation renders the particle no longer infectious or pathogenic. Neutralising antibodies are part of the humoral response of the adaptive immune system against viruses, intracellular bacteria and microbial toxin. By binding specifically to surface structures (antigen) on an infectious particle, neutralising antibodies prevent the particle from interacting with its host cells it might infect and destroy. Immunity due to neutralising antibodies is also known as sterilising immunity, as the immune system eliminates the infectious particle before any infection takes place.

BAU is the WHO unit of measurement for the recognition of neutralizing antibodies in the blood? BAU / ml (BAU = Binding Antibody Units).

The Sensitivity of SARS-CoV-2 Nab Test KIT: 99.09% (95%CI: 94.31%-99.95%)
The Specificity of SARS-CoV-2 Nab Test KIT: 98.89% (95%CI: 93.10%-99.94%)

  • Below a value of 21.8 Binding Antibody Units (BAU), we assume that the tested person has no immune protection against Covid-19.
  • Expected titer after first vaccination: 20-300 BAU / ml
  • Expected titer after second vaccination:> 300 BAU / ml
  • 1000 BAU or more is determined as the minimum required level of antibodies for protection against Covid-19.

The entire process will take around 18-20 minutes including taking the capillary blood sample (finger prick.) The test itself only takes seven seconds to process however, the blood sample and cassette need to be left for 15 minutes before being processed.